Measurement of connective tissue parameters in serum for diagnosis and follow-up of liver fibrosis

Assessment of new hyaluronic acid assays and their impact on FibroMeter scores

BACKGROUND

We compared three hyaluronic acid (HA) assays and analyzed the impact of their variations on FibroMeter scores.

METHODS

In a test group of 165 patients, HA levels were assessed with the commonly used ELISA assay from Corgenix, a new ELISA assay from Teco and an immunoturbidimetry assay from Wako, this latter tested across three different instruments. Five different FibroMeter scores were calculated.

RESULTS

Correlation across the three assays (r(s) between 0.969 and 0.995) was very good. Means of differences (d) were lower when the immunoturbidimetry assay was compared on different instruments: d between -3.4 and 2.0 μg/L. However, a higher value for HA measurement was observed with Corgenix assay, compared to the other two assays (Teco and Wako): d between 27.1 and 36.4 μg/L. The assessment also demonstrated that HA variations had very little impact on FibroMeter scores: 0.0117 for virus and 0.0416 for alcoholic fibrosis scores, and between 0.58 and 1.71 for the area of fibrosis (expressed in percentage).

CONCLUSIONS

The two new assays found lower values of HA, as compared to the Corgenix assay. However, these differences had very little impact on FibroMeter scores and had no impact on clinical evaluation of liver fibrosis.

Multivariate Discriminant Function Based on Six Biochemical Markers in Blood Can Predict the Cirrhotic Evolution of Chronic Hepatitis

Background: Serologic markers have been proposed for monitoring hepatic fibrosis in chronic active liver disease. Because none of these markers, when used singly, is totally satisfactory, we developed and evaluated a multivariate approach.

Methods: We studied two cohorts of chronic hepatitis (54 patients) and cirrhosis patients (49 patients) to identify a panel of biochemical markers that discriminates between the two diseases. Using multivariate discriminant analysis, we selected a function, based on the concentrations of six biochemical markers (fibronectin, prothrombin, pseudocholinesterase, alanine aminotransferase, manganese superoxide dismutase, and N-acetyl-β-glucosaminidase). We then prospectively validated this function on a second temporal cohort of patients.

Results: Multivariate discriminant analysis correctly classified 93.7% of patients (94.3% of chronic hepatitis and 92.9% of cirrhosis patients) in the first cohort and 85% of patients (89.5% of chronic hepatitis patients and 81% of cirrhosis patients) in the second cohort.

Conclusions: Discriminant analysis of results of six inexpensive biochemical markers provides a high predictive value for differentiation between liver cirrhosis and chronic hepatitis. Consequently, these biochemical markers condensed into a multivariate discriminant analysis value for each patient provide information that can be contributory for subsequent options during the evolution of the natural history of chronic hepatitis.

Serum markers of hepatic fibrogenesis in chronic hepatitis type C treated with alfa-2A interferon

Hepatic fibrogenesis is a dynamic process which characterizes the course of chronic hepatitis. It has stimulated interest in the possible effect of interferon therapy on liver fibrosis. We have evaluated a panel of serum markers of fibrogenesis, namely N-terminal procollagen III peptide (PII-INP), C-terminal procollagen I peptide (PICP), laminin and hyaluronate in 35 patients with chronic hepatitis type C, before, during and after interferon treatment. Before treatment, PIIINP was elevated in 8.5%, 44% and 71% of patients with chronic persistent hepatitis, chronic active hepatitis and cirrhosis, respectively, while the corresponding figures for PICP were 0%, 50% and 46%, and for laminin 16.5%, 70% and 71%; hyaluronate was elevated in only five out of seven patients with cirrhosis. Patients with high PIIINP levels at presentation and a persistent response to treatment showed persistent normalization of this parameter, which was not observed in non-responders. In contrast, the other markers showed no significant correlation with interferon response. These results indicate that PIIINP correlates with interferon response in chronic hepatitis type C.

Assessment of the fibrogenetic activity in chronic pancreatitis. The role of circulating levels of extracellular matrix components

Determination of circulating levels of extracellular matrix components has been proposed as a reliable method to assess the activity of fibrogenetic processes. Therefore, we aimed to analyze circulating levels of laminin, fibronectin, and procollagen III peptide (PIIIP) in patients with chronic pancreatitis (CP) and to correlate them with the morphological and functional stage, and duration of the disease. Thirty patients with CP and 18 healthy controls were studied. Serum PIIIP concentrations (RIA), but not fibronectin (RID) and laminin (RIA), were abnormally high in 8 patients with CP. No correlation was found between circulating levels of extracellular matrix components and both functional and morphological stage and duration of CP. Nevertheless, patients with elevated serum PIIIP levels tend to have a more advanced CP (morphological and functional changes) than those with normal levels after a similar duration of the disease. We hypothesize that whereas functional and morphological findings reflect the cumulative effect of chronic inflammation on the pancreas, serum PIIIP concentrations would reflect the activity of the fibrogenetic process within the gland at the time of sampling. The results shown in the present study may be considered a starting point for longitudinal studies that examine the relationship between serum PIIIP or other markers for fibrogenetic activity and evolution of CP.

Serum laminin in hepatic schistosomiasis

Serum laminin levels were measured in patients with chronic hepatic schistosomiasis. A significant increase in the mean serum laminin level was observed in 14 patients with hepatosplenic schistosomiasis (2.57 +/- 0.83 units/ml [standard deviation]) compared to the level in 10 patients with the hepatointestinal form of the disease (1.38 +/- 0.45 units/ml) and in the control group of 10 (1.15 +/- 0.31 units/ml). In the hepatosplenic patients there was a significant direct relation between serum laminin and percutaneous splenic pulp pressure (r = 0.68). However, this relation was not observed with either liver function tests or levels of N-terminal propeptides of type III procollagen. These findings are compatible with an increased production of laminin in hepatosplenic schistosomiasis, which may be related to the observed enlarged liver and spleen basement membranes in such disease.

The prognostic value of extracellular matrix component concentrations in serum during treatment of adult respiratory distress syndrome with extracorporeal CO2 removal

The time-dependent concentrations of hyaluronan, aminoterminal propeptide of type III procollagen, and laminin were determined in sera of 16 patients with severe adult respiratory distress syndrome during treatment with an extracorporeal CO2 removal device. Patients were classified according to lung parameters as responders (n = 10) and non-responders (n = 6) to extracorporeal CO2 removal. At the beginning of treatment strongly elevated serum concentrations of all studied extracellular matrix components were found. During the first 6-11 days of treatment the concentrations of aminoterminal propeptide of type III procollagen and hyaluronan increased further in non-responders but decreased in the majority of responders, while laminin decreased in both groups. No significant correlations were found between the serum concentrations of connective tissue components and the parameters of lung function. By non-parametric analysis of variance, significant differences between responders and non-responders according to treatment time could be established. By analysing the time course of the serum concentrations of hyaluronan and aminoterminal propeptide of type III procollagen, a total differentiation between responders and nonresponders was made possible by the trends of these analytes as early as three days after the start of treatment. The determination of aminoterminal propeptide of type III procollagen and hyaluronan in serum of patients with adult respiratory distress syndrome might therefore have prognostic significance in extracorporeal CO2 removal.

Aminoterminal propeptide of type III procollagen: a marker of disease activity in schistosomal patients

The serum concentration of aminoterminal propeptide of type III procollagen was measured in 44 Egyptian healthy controls and 29 patients with hepatosplenomegaly originating from endemic areas for schistosomiasis in Egypt. Patients were classified into two main groups according to the histopathological pattern of the liver biopsy: patients with active schistosomal liver fibrosis and patients with inactive schistosomal liver fibrosis. Serum aminoterminal propeptide of type III procollagen levels were elevated in most of patients with active fibrosis but not in those with inactive schistosomiasis. From the present work, it is suggested that aminoterminal propeptide of type III procollagen can be used as a marker for active fibrogenesis in patients with schistosomal liver fibrosis.

Biochemical markers of hepatic fibrosis

Most liver diseases lead to a pathobiochemical reaction termed liver fibrosis. This is a dynamic process implying different rates of progression or regression. Thus, histological examination of a liver biopsy is essential for a diagnosis but biochemical tests are necessary for assessing the activity of the process and monitoring its evolution. We review the most important constituents of liver connective tissue and the biochemical tests developed for evaluating liver fibrosis. The aminopeptide of type III procollagen is the most widely used parameter: two different radioimmunoassays have been developed with different affinities for the two circulating forms of the molecule. The determination of serum P3P reveals an elevation of blood levels both in acute and chronic liver diseases. In the first, serum P3P is an index of hepatic necrosis and inflammation which correlates with other biochemical parameters. In the second it is an index of active fibrogenesis. Moreover, in primary biliary cirrhosis this parameter is an independent prognostic variable and an important predictor of survival. Other immunoassays exist for different collagen cleavage products, but their clinical value is not established. Laminin and fibronectin are the principal structural glycoproteins in liver. Fibronectin determination does not seem to be of clinical value in liver disease. In contrast, serum laminin correlates with the severity of portal venous pressure in advanced liver disease. Its concentration parallels the severity of varices and may indicate the risk of bleeding. Hyaluronate is a high molecular weight polysaccharide, raised serum concentrations reflect both its increased synthesis by activated fibroblasts and its impaired catabolism by the liver. Thus, it may be useful for evaluating and monitoring the progression of chronic liver disease. The measurement of the activity of prolyl 4-hydroxylase as well as that of lysine oxidase and other enzymes has been proposed, but their clinical value is not sufficiently demonstrated. A panel of tests (e.g., laminin, hyaluronate and the aminopeptide of type III procollagen) seems to be recommended for a biochemical assessment of liver fibrosis in clinical practice.

Collagen peptidase and type III procollagen peptide serum levels in chronic liver diseases

The concentration of the N-terminal peptide of procollagen III and the activity of collagen peptidase (PZ-peptidase) were measured in sera from 92 patients with chronic liver disease. In patients with liver cirrhosis and chronic hepatitis with transformation of liver structure, high values were found for both variables compared with hepatoses and chronic hepatitis without transformation. The concentration of procollagen III peptide and the activity of collagen peptidase in serum increased with increasing degrees of fibrosis and, even more markedly, with increasing degrees of mesenchymal activity in the liver.

Follow-up of the serum levels of extracellular matrix components in acute and chronic pancreatitis

Time-dependent serum concentrations of extracellular matrix proteins were studied in 32 patients with pancreatitis in order to find potential markers of the reparative response during the disease. Patients were subdivided by clinical and biochemical criteria: severe acute pancreatitis (n = 10), moderate acute pancreatitis (n = 17), and acute attack of chronic pancreatitis (n = 5). Serum and plasma samples were collected on days 1-7, 10, 14, and 21 for measurements of the aminoterminal propeptide of type III procollagen (PIIINP), hyaluronic acid, laminin, fibronectin, and routine clinical-chemical parameters. During an acute attack of chronic pancreatitis all parameters were within the reference range. In moderate acute pancreatitis concentrations of PIIINP, laminin, and hyaluronic acid fluctuated around the upper reference limit, but declined to mid-normal levels at day 21. In severe acute pancreatitis all three parameters increased. In patients who died as a consequence of sepsis and multi-organ failure the increase in PIIINP, laminin and hyaluronic acid was much more pronounced and paralleled by a decrease in plasma concentrations of fibronectin. In conclusion, this study revealed a relation between the severity of acute pancreatitis and the increase in serum concentrations of extracellular matrix components, especially PIIINP.

Cryptogenic chronic active liver disease. Evaluation of serum aminoterminal peptide of type III procollagen as a marker of histological activity

Sera from 64 patients with HBsAg-negative chronic liver disease with or without cirrhosis were investigated for aminoterminal peptide of type III procollagen (sP-III-P) as a suitable marker of hepatic fibrosis; 244 healthy control subjects were included in the study. A close correlation (p less than 0.01) between sP-III-P levels and histological activity was observed; on the contrary, no correlation was found between the same serum marker of liver fibroplasia and biochemical activity or clinical severity of the disease. We conclude that sP-III-P as a suitable marker of liver overload of collagen fibers is strongly correlated with the histological activity of the disease. Local immune reactions produce soluble substances that might stimulate fibroblastic activity. The test has a significant sensitivity and a very high specificity as a marker of chronic liver disease with histological activity.

Thioacetamide-induced cirrhosis-like liver lesions in rats--usefulness and reliability of this animal model

Long term administration of thioacetamide (0.03% in tap water) results in a characteristic lesion in rat liver, which corresponds to cirrhosis-like patterns of micronodular cirrhosis type after treatment over 3 months. During its development a reproducible temporal course of biochemical and morphological changes can be recognized. After withdrawal of the toxic agent this lesion persists for about 2 months. Then the cirrhosis-like alterations recede and a proliferation of bile ducts predominates, which is associated with increasing portal fibrosis altering the pattern and relatively enhancing the total collagen content of the liver. Considering these peculiarities, the TAA-model is suitable for investigations into connective tissue metabolism in the fibrotic liver and cirrhosis-like patterns. Search for and test of therapeutic principles should be done during TAA-administration (prophylactic agents) or within 2 months after withdrawal of toxic agents (therapeutics).

Estimation of the production rates of serum aminoterminal propeptide of type III procollagen and laminin in human fibrotic liver

The concentrations of laminin, a high molecular weight non-collagenous glycoprotein of basement membranes, and of the N-terminal propeptide of type III procollagen were determined in the serum of the liver outflow vascular region (hepatic vein) and of a peripheral vein (cubital vein) in patients with chronic liver diseases (fibrosis, cirrhosis, unspecified histology; n = 173), in order to determine their secretion rates from the injured livers. The mean levels of laminin (1.84 kU/l) and of procollagen peptide (28.0 micrograms/l) in hepatic vein were significantly higher (about 9.5% at p less than 0.02, and 37% at p less than 0.001, respectively) than those in the periphery (1.68 kU/l and 20.4 micrograms/l, respectively). In chronic liver diseases, however, laminin and procollagen peptide concentrations in the hepatic vein were lower than or equal to those in the cubital vein in 18% and 27% of patients, respectively. The highest regional differences of the concentrations were noted in cirrhotic subjects. The serum levels of laminin (rs 0.93) and of procollagen peptide (rs 0.73) in hepatic and in cubital vein are highly positively correlated (p less than 0.001), but the levels of procollagen peptide in hepatic vein are only weakly but still significantly statistically related with those of laminin (rs 0.446, p less than 0.001). Similarly, the hepatic-cubital venous concentration differences of both proteins are weakly (rs 0.312) but significantly (p less than 0.001) correlated. On the basis of several assumptions we estimated secretion rates from the livers of 120 U.min-1 for laminin, and 5.7 micrograms.min-1 for procollagen peptide.(ABSTRACT TRUNCATED AT 250 WORDS)